To determine whether alpha-methyl-para-Tyrosine decreases pineal melatonin secretions and 6-hydroxymelatonin sulfate excretion. The change in AMPT induced melatonin secretion will be correlated to clinical symptoms and indirectly to assess the degree of reduced CNS norepinephrine activity due to AMPT. This ultimately may be used as a screening test for depressed patients to assist in choosing the appropriate medication.